The present invention relates to a thin layer evaporator comprising a container forming a body, a drive shaft projecting into the same from one front face thereof and a rotor fixed thereto having one or more conically outwardly widening evaporator areas and whose evaporator chamber is connected to the body and a heating chamber separated from the body, the starting product being charged at the inner periphery of the evaporator areas, spreads outwards from there in film-like manner and the concentrate is removed from the outer periphery by means of a draw-off pipe.
Thin layer evaporators of the aforementioned type are known (British Pat. No. 1 132 640, Swedish Pat. No. 184 175) or form the subject matter of an earlier-dated U.S patent application Ser. No. 688,411, filed Jan. 2, 1985. In these evaporators, evaporator areas generally slope conically, either in the same direction so that they are roughly parallel to one another, or directed oppositely to one another, so that the corrugated tube with a similar construction is obtained. These evaporators can be operated in single stage or multistage manner, so that the starting product is either supplied simultaneously to all the evaporator areas (single stage), or to only part of the evaporator areas (multistage), the concentrate being removed by means of a draw-off pipe and transferred to the other evaporator areas.
In the case of these thin layer evaporators, the front face of the rotor is located on the drive shaft, which has to absorb all the forces. The support structure of the rotor must be constructed in a corresponding stable manner, in order to be able to absorb the dynamic forces. This more particularly applies if the evaporator is positioned horizontally, when the gravity of the rotor acts at right angles to the drive shaft. As all the forces have to be passed to the outside via the drive shaft, a correspondingly complicated bearing is required outside the container and this leads to additional construction height or, in the case of a horizontal arrangement, construction length.